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Optimize network throughput for Azure virtual machines

In this article

Azure virtual machines (VM) have default network settings that can be further optimized for network throughput. This article describes how to optimize network throughput for Microsoft Azure Windows and Linux VMs, including major distributions such as Ubuntu, CentOS, and Red Hat.

Windows VM

If your Windows VM supports Accelerated Networking, enabling that feature would be the optimal configuration for throughput. For all other Windows VMs, using Receive Side Scaling (RSS) can reach higher maximal throughput than a VM without RSS. RSS may be disabled by default in a Windows VM. To determine whether RSS is enabled, and enable it if it's currently disabled, complete the following steps:

See if RSS is enabled for a network adapter with the Get-NetAdapterRss PowerShell command. In the following example output returned from the Get-NetAdapterRss, RSS is not enabled.

The previous command does not have an output. The command changed NIC settings, causing temporary connectivity loss for about one minute. A Reconnecting dialog box appears during the connectivity loss. Connectivity is typically restored after the third attempt.

Confirm that RSS is enabled in the VM by entering the Get-NetAdapterRss command again. If successful, the following example output is returned:

Linux VM

RSS is always enabled by default in an Azure Linux VM. Linux kernels released since October 2017 include new network optimizations options that enable a Linux VM to achieve higher network throughput.

Ubuntu for new deployments

The Ubuntu Azure kernel provides the best network performance on Azure and has been the default kernel since September 21, 2017. In order to get this kernel, first install the latest supported version of 16.04-LTS, as follows:

New and existing VMs can benefit from installing the latest Linux Integration Services (LIS). The throughput optimization is in LIS, starting from 4.2.2-2, although later versions contain further improvements. Enter the following
commands to install the latest LIS:

sudo yum update
sudo reboot
sudo yum install microsoft-hyper-v

Red Hat

In order to get the optimizations, it is best to create a VM with the latest supported version by specifying the following parameters:

New and existing VMs can benefit from installing the latest Linux Integration Services (LIS). The throughput optimization is in LIS, starting from 4.2. Enter the following commands to download and install LIS: